1. Field of the Invention
The present invention relates to ink jet printing apparatus having a plurality of discrete orifice arrays which cooperate in printing operations and more particularly to a positioning and control system of such printing apparatus that enables use of readily insertable print/cartridges.
2. Description of Background Art
There are known drop-on-demand ink jet printer systems in which a print head carriage bearing a print head traverses across the width of a print medium in line printing operation. Between line printing sequences, the print medium is advanced to prepare for the next sequence. One useful approach for such printing systems is to construct the print head element as part of a disposable print/cartridge which contains an ink supply, drop-generating structures and electrical connections adapted for coupling to the printer, which provides drop-generating energy to such an inserted print/cartridge.
Heretofore, such disposable print/cartridge units have been employed one unit at a time in the printing operation and precise positioning and control of the print/cartridge's printing line locus, relative to the print medium is not required. That is, a particular print/cartridge, once inserted, will establish its particular line locus vis-a-vis the printer's print zone. Thus, variation of line locus between different print/cartridges (e.g. because of low tolerances within the print/cartridge and in the print/cartridge printer interface) has not presented problems.
However, there exist applications where it would be desirable to use a plurality of such readily insertable print/cartridges, cooperatively, in page-printing. For example, it may be desired to print more than one color of ink on a printed page. Or, it may be desired to use a plurality of cooperative print/cartridges to increase the page-printing speed of the printer. I have found that in using more than one print/cartridge for cooperative printing on a single page, it is desirable to precisely interrelate the printing loci of those print/cartridges. Otherwise printing artifacts can occur, e.g. due to horizontal and/or vertical misregistration of the component line portions contributed by the respective print/cartridges.
The problem of providing precise interrelation for a plurality of discrete orifice arrays is difficult, even in apparatus where the orifice arrays form relatively permanent parts of a printer. When the orifice arrays comprise portions of insertable print/cartridges the problem is even more difficult, for the print/cartridges should be inexpensive, dictating a minimum of high tolerance construction features and low tolerance assembly.